Multicast forwarding and FortiGate units
In both transparent mode and NAT mode you can configure FortiGate units to forward multicast traffic.
For a FortiGate unit to forward multicast traffic you must add FortiGate multicast security policies. Basic multicast security policies accept any multicast packets at one FortiGate interface and forward the packets out another FortiGate interface. You can also use multicast security policies to be selective about the multicast traffic that is accepted based on source and destination address, and to perform NAT on multicast packets.
In the example shown below, a multicast source on the Marketing network with IP address 192.168.5.18 sends multicast packets to the members of network 18.104.22.168. At the FortiGate unit, the source IP address for multicast packets originating from workstation 192.168.5.18 is translated to 192.168.18.10. In this example, the FortiGate unit is not acting as a multicast router.